回調

const cb = new JSCallback(
  (a: number, b: number): number => a + b,
  { args: [FFIType.int32, FFIType.int32], returns: FFIType.int32 },
);

cb.call(2, 3); // → 5

function makeAdder(x: number): JSCallback {
  return new JSCallback(
    (y: number): number => x + y,
    { args: [FFIType.int32], returns: FFIType.int32 },
  );
}

const add5 = makeAdder(5);
add5.call(3); // → 8
add5.close();

const cb = new JSCallback(
  (x: number): number => x * 2,
  { args: [FFIType.int32], returns: FFIType.double, threadsafe: true },
);

cb.threadsafe; // → true
cb.call(5);    // → 10
cb.close();

const cb = new JSCallback((x: number): number => x * 3, {
  args: [FFIType.int32],
  returns: FFIType.int32,
  threadsafe: true,
});

// cb.ptr 是真實函數地址，可通過 CFunction 包裝後調用
const fn = CFunction({ args: [FFIType.int32], returns: FFIType.int32, ptr: cb.ptr });
fn(7); // → 21
fn.close();
cb.close();

cb.close();
cb.call(1); // 拋出異常：句柄無效

import { JSCallback, FFIType } from 'arkffi';

const add = new JSCallback(fn1, { args: [FFIType.int32, FFIType.int32], returns: FFIType.int32 });
const mul = new JSCallback(fn2, { args: [FFIType.int32, FFIType.int32], returns: FFIType.int32 });

add.call(3, 4); // 7
mul.call(3, 4); // 12

add.close();
mul.close();

// C: void foreach(int* arr, int len, void (*cb)(int));
const cb = new JSCallback(
  (x: number): number => x * 2,
  { args: [FFIType.int32], returns: FFIType.int32 },
);

ffi.callMixed(handle, 'foreach', 'ipi', 'v', [arrPtr, len, cb.ptr], []);
cb.close();